Line a 9x13 pan with foil and spray with non-stick spray. Make sure to include extra foil on the two ends, which will help you pull them out of the pan later.
In a food processor, pulse the Golden Grahams until they are roughly broken - there should be a mix of fine crumbs, small pieces, and larger pieces. If you don’t have a food processor, place the cereal in a zipper bag and crush them with a rolling pin or other heavy object.
3 cups Golden Grahams cereal
In a large pot melt the butter over medium heat. Continue cooking until the butter is foamy and golden brown (careful, it will burn easily). For more tips, read this guide on how to brown butter. 1 cup (2 sticks) salted butter
Turn the heat to low and add marshmallows, vanilla, and salt. Stir with a rubber spatula until the marshmallows are completely melted.
2 10 oz bags mini marshmallows, ¾ teaspoon vanilla, ½ teaspoon kosher salt
Add the rice krispies and crushed Golden Grahams, then stir until well combined.
5½ cups rice krispies cereal, 3 cups Golden Grahams cereal
Pour the mixture into the prepared pan, then use the spatula to press gently until it’s roughly even across the pan. Be sure to press very gently for soft rice krispie treats. To get them perfectly flat, spray a piece of plastic wrap lightly with non-stick spray. Lay it across the rice krispie treats and finish pressing with a flat-bottomed measuring cup until they are even. You can also skip the plastic and use a greased spoon or rubber spatula to do this! Allow to cool to room temperature (or just dig in while they’re warm!), then cut and serve.